The present invention relates to a microprocessor and, more particularly, to a microprocessor to which a coprocessor can be connected for co-operation.
In a microprocessor formed on a single semiconductor chip, there is a limitation in the number of circuit elements which can be integrated in a single chip. Therefore, it is difficult to realize a single chip microprocessor that executes, at a high speed, high level instructions such as a floating-point arithmetic operation, a function arithmetic operation, etc. In order to solve this problem, a main microprocessor is made to co-operate with a coprocessor which executes the high level instructions for the main microprocessor.
However, a system is initially developed with the use of a microprocessor, and then its designer finds it necessary to use a coprocessor. Therefore, the system designer must first develop a program necessary for using one microprocessor. Thereafter, when the coprocessor is necessitated, the designer amends the program so as to fit with the system using both the microprocessor and coprocessor. Thus, the system designer or the user of the microprocessor is required to form the program for using the coprocessor twice.